Process and apparatus for utilizing submerged combustion



June 9, 1959 R. v. HEINZE 2,890,166

PROCESS AND APPARATUS FOR UTILIZING SUBMERGED COMBUSTION Filed Oct. 14, 1952 INVENTOR. ROBERT V. HEINZE BY m w ATT'YS United States Patent PROCESS AND APPARATUS FOR UTILIZING SUBMERGED COMBUSTION Application October 14, 1952, Serial No. 314,731

12 Claims. (Cl. 208102) This invention relates to a new and improved method and apparatus for utilizing submerged combustion.

Submerged combustion burners are known in the art and have been used very satisfactorily in heating liquids, as, for example, in heating pickling baths containing sulfuric acid. In most instances, heating with submerged combustion burners involves the employment of open vats or containers for the liquid and the combustion gases are permitted to escape through the liquid that is being heated and out the top of the container. The incondensible gases resulting from the combustion have made it impractical heretofore to utilize submerged combustion for steam generation and many other processes requiring a closed system.-

One'of the objects of the present invention is to provide a method and an apparatus in which submerged combustion burners are used in a closed system.

Another object of the invention is to provide a method and an apparatus wherein submerged combustion burners are used in closed vessels either at superatmospheric or subatmospheric pressures.

An additional object of the invention is to provide a method and apparatus in which a submerged combustion burner is employed in a system provided with a means for separating incondensible gases from fluids heated by submerged combustion.

A ,further object of the invention is to provide a new and improved method and apparatus for the generation of steam by submerged combustion.

An additional object of the invention is to provide a new and improved apparatus for carrying on chemical reactions with the assistance of submerged combustion.

Another object of the invention is to provide a new and improved apparatus for cracking and/or reforming high molecularweight materials such as petroleum hydrocarbons in order to produce different molecular weight or molecular structure gases, vapors and liquids.

An additional object of the invention is to provide a new and improved method and apparatus wherein hot liquids are continuously recirculated in heat exchange relationship with a submerged combustion burner.

Another object is to provide a new and improved method and apparatus wherein hot liquids are continuously recirculated in heat exchange relationship with a submerged combustion burner and incondensible gases and products are simultaneously separated from the circulating body of material.

. A further object is to provide a method of and apparatus for processing liquids in which a submerged combustion flame burning in direct contact with the liquid acts as a lift pump to assist in recycling of the liquid externally of the heating chamber.

Other objects will be apparent by reference to the following description in conjunction with the accompanying drawings in which Fig. 1 represents an elevational view partly in section and with parts broken away of one form of apparatus I suitable for the practice of the invention; and

Fig. 2 represents a modified portion of the apparatus illustrated in Fig. l.

The apparatus illustrated in the drawings comprises a cylindrical closed heat exchange chamber 1 containing a submerged combustion burner 2, a cylindrical gas separating chamber 3 communicating with said heat exchange chamber 1 and a cylindrical flash chamber 4 communicating with said gas separating chamber 3 and also With said heat exchange chamber 1.

The communication between said heat exchange chamber 1 and said gas separating chamber 3 can be eflected by means of conduits 5 and 6 connected together at the flanges 7 and 8. In a similar manner the gas separating chamber 3 can communicate with the flash chamber 4 through conduits 9 and 10 which are connected by means of flanges 11 and 12. Communication between the flash chamber 4 and the heat exchange chamber 1 is estab* lished by means of a conduit 13.

For control purposes it is desirable to provide check valves 14, 15, 16, 17 and 17a and valves 18, 19, 20, 21, 22, 23, 24 and 25. For observation purposes it is desirable to provide thermometer wells 26, 27 and 28, a pressure gauge 29 and a level gauge 30. A cylindrical combustion chamber 31 around the lower end of the submerged combustion burner 2 is provided to facilitate distribution of heat to the liquid or other fluid which is being heated. Conduit 32 is an inlet conduit for materials which are to be subjected to heating in carrying out processes in the apparatus described. Conduit 32 may be varied as to location and number of inlets for the purpose of introducing materials to the optimum advantage of the processing being carried on. For instance, conduit 32 might well be tied into conduits 9 and 10, or into chamber 4, or into conduit 13, or chamber 31. Conduit 33 is an outlet conduit for the release of incondensible gases produced as a result of the submerged combustion and/or as a result of reactions carried out in the heat exchange chamber 1. Conduit 34 is provided for the release of vapors from flash chamber 4. Conduit 35 is an inlet conduit for the introduction of special materials, e.g., auxiliary reactants or catalysts, in particular processes. Conduit 35 may be varied as to location for the purpose of introducing materials either above or below the liquid level. Further, the location of conduit 35 can be changed or similar additional conduits added to introduce special materials into chambers 1, 3 and/or 31. Conduit 36 is an outlet conduit for the removal of products. At least one such outlet is necessary. Additional outlets can be provided at various locations such as from chambers 1, 3 and 4, and from conduits 9, 10 and 13. This is sometimes necessary to avoid destruction, or alteration of products that undergo chemical or physical changes if retained in the apparatus beyond the point of optimum production or generation.

The submerged combustion burner which is illustrated diagrammatically in the drawings is preferably of the type described in See et al., US. Patent 2,118,479. In the type of burner shown, a fuel gas, such as natural gas, or other suitable type of fuel gas is introduced through a main gas conduit 37 and a pilot gas conduit 38. Support for combustion is provided through a main air conduit 39 and a pilot air conduit 40. The combustion occurs at a burner plate 41 located within the combustion chamber 31. The operation of the submerged combustion burner can be controlled automatically in a number of different ways but since such controls do not form a part of the invention they will not be discussed in detail.

The apparatus described is especially useful for generating steam from water. The water is introduced into the heat exchange chamber 1 through conduit 32 controlled by valves 14 and 18. It is heated in the combustion chamber 31 by the submerged combustion burner 2 which acts as an air lift causing the heated water to flow upwardly through conduits and 6 to gas separating chamber 3. As thewater passes upwardly through the conduits 5 and 6 it loses its incondensible gases which are. released through conduit 33 controlled by valves 15 and 19. The gas-free hot water then flows into the flash chamber 4 where it flashes off as steam which is released through the conduit 34 controlled by valves 16 and 20. Steam produced in this manner is usable for heating purposes and for the operation of turbines and other power units. Where it is desired to produce hot water the latter can be withdrawn from the system through the conduit 36 controlled by valve 24.

The liquid level in the apparatus is maintained by adding additional water or other material to be processed through the conduit 32 and is sufficiently high to permit a continuous overflowing of the liquid from heat eX-v change chamber 1 through conduits 5 and 6 to gas separating chamber 3. Thus, the walls of the heat exchange chamber 1 act as a baffle and assist in the release of in-' condensible gases. Although it is preferable to provide two separate units 1 and 3, these can also be regarded as a single unit comprising two chambers separated from each other by a baflle.

In a typical operation using an apparatus of the general type described, thirty-two pounds of water were run through the aparatus in fifteen minutes of continuous operation. The temperature of the water was raised from 61 F. to 280 F. The operation was varied at will. At one time the temperature of the outlet steam rose to 390 F. During another period hot water free from gases of combustion was produced at 175 F.

The apparatus described is also applicable to the heating of petroleum stock with the production of gas and other products as a result of vaporization and cracking. Unless it is desired to produce oxidized products the fuel gases and air introduced through the conduits 37 to 40, inclusive, should be regulated to produce a neutral flame or one deficient in oxygen. Otherwise, the petroleum stock fed into the unit through conduit 32 will oxidize and increase the size of the flame at or beyond the burner tip 41.

According to one method of procedure a petroleum stock of the type used as a charging or cycling stock for a catalytic cracking unit is introduced into a heat exchange chamber 1 through conduit 32 where it is brought into direct contact with the submerged combustion burner flame in the combustion chamber 31. Due to the lack of oxygen the petroleum stock will not burn. It is merely heated by the flame. Depending upon the temperature conditions and the rate at which the petroleum stock is circulated the heating can be effected in order to cause gasification, vaporization'and/or cracking of the petroleum stock. The incondensible gases, as well as some gasified petroleum products are released through conduit 33. The petroleum stock which is charged into heat exchange chamber 1 is lifted upwardly by the action of the submerged combustion burner flame and flows into chamber 3 through conduits 5 and 6. From chamber 3 it passes through conduits 9 and 10 to chamber 4. Condensible vapors are released intermittently or continuously through conduit 34 by opening valve 20. Liquid products are removed from chamber 4 through conduit 36 either intermittently or continuously by opening valve 24. The petroleum stock is recycled through conduit 13 several times until the desired product distribution is obtained. Cracking occurs at temperatures around 650 F. and higher. Gasification and vaporization occur at lower temperatures.

In one series of operations the petroleum stock was recycled three times. The oil had a temperature of 180 F. as it left the heat exchange chamber 1. The release of the products of combustion and petroleum gases is effe e y Opening the valves 19 and 20. In some cases it is desirable to retain the petroleum vapors along with the heated oil and in these cases the valve 20 is closed. In other cases it is desirable to permit only a small flow of escaping gas through the gas release line 33 by opening valve 19 slightly. The vapors obtained from outlet 34 were ignited and burned readily. They were invisible before igniting. There was no hot oil spewing or spitting out with the gases. In some cases it is desirable to extend the conduits 33 and/ or 34 to points below the liquid level of the liquids in chambers 3 and 4, respectively.

The apparatus shown in Fig. 2 is a modification of a portion of the apparatus shown in Fig. 1 in which like parts are indicated by like numerals. In the apparatus shown in Fig. 2, auxiliary air and/ or steam and/ or other material is supplied through conduit 42 to a cylindrical shell 43 which surrounds the cylindrical combustion chamber 31 and is provided with an opening 44 where the excess air can escape into the liquid which is being processed. This type of apparatus is especially useful where it is desired to control the flame temperature and also in those instances where it is desired to oxidize the liquid being treated. If control of the flame temperature is desired without any oxidizing action, a gas such as nitrogen can be introduced through conduit 42.

The temperature of the flame at the burner plate 41 will vary somewhat depending upon the fuel being used. Natural gas has flame temperature around 2900 F. which is too hot for processing many solutions such as sugar solutions, asphalt and solutions containing substances that tend to carbonize readily.

In the event it is desired to hold the pressure in flash chamber 4 higher than that in the heat exchange chamber 1 the hot liquid is boosted to the flash chamber 4 by means of a submerged booster pump or other mechanical booster device (not shown) which can readily be installed at the connection 11, 12 of conduits 9 and 10. In this case it is also necessary to provide some pressure regulating means (not shown) in conduit 13.

Due to the fact that the submerged combustion burner 2 produces a lifting effect in the body of the liquid in heat exchange chamber 1 it is ordinarily unnecessary to provide a pump for circulating the liquid through the several zones where gases and vapors are released and products are recovered. It is only necessary to establish a body of liquid in heat exchange chamber 1 sufficiently large to overflow into gas separating chamber 3. Naturally, the liquid level in gas separating chamber 3 and flash chamber 4 will eventually attain approximately the level of the body of liquid established in heat exchange chamber 1. In the generation of steam, water is introduced continuously from inlet conduit 32 through valve 18 and vapors are withdrawn continuously through conduit 34 controlled by valve 20.

In case it is desired to increase the rate of circulation of the liquid a booster pump (not shown) is installed in conduits 9 and 10 or in conduit 13, and if it is desired to maintain a greater pressure in chambers 1 and 3 than in chamber 4, the booster pump is installed in conduit 13 and pressure release valves are installed in conduits 10 and 33.

Where the apparatus is used as a hot water heater makeup water is introduced through conduit 32 controlled by valve 18 and hot water is withdrawn through conduit 36 controlled by valve 24. Suitable thermostatic and level controls are provided to control the temperature of the water and the water level in the heat exchange chamber.

Where the apparatus is used for cracking petroleum oils the cracking stock is preferably introduced through conduit 32 and/or conduit 35; incondensible gases are separated through conduit 33 controlled by valve 19; 'condensible vapors are withdrawn through conduit 34 controlled by valve 20 and residual oils are removed through conduit 36 controlled by valve 24.

In reforming operations where it is desired to change the nature of'the product distribution of a petroleum oil auxiliary reactants and catalysts can be added through conduit 35 controlled by valve 21, or if desired, through additional inlets provided for that purpose. For example, in hydroformin'g processes materials consisting primarily of hydrocarbons boiling in the gasoline range are heated at temperatures in excess of 500 F. with a solid catalyst in the presence of free hydrogen or materials capable ofsupplying hydrogen. Free hydrogen can be introduced through conduit 35 and/or conduit 42 (Fig. 2). Similarly, solvents, diluents, and reactants can introduced into the process through conduit 35 in order to control the reaction or to bring about a particular type of reaction.

The method and apparatus lends itself to the evaporation of water or generation of steam by introducing the water, for example, through conduit 35 so that it may be converted into steam by contact with hot material, such as high boiling petroleum stock, which is introduced into, chamber 1 through conduit 32 and circulated through the apparatus back into chamber 1 from chamber 4. The necessary stock is drawn off through the outlet 36 in order to keep the hot material of the proper consistency.

The method and apparatus lends itself to the purification of gasoline or naphthas in oil.refineries by cycling hot water or hot oil through chambers 1, 3 and 4 and introducing the gasoline or naphtha to be purified through inlet 35. Thus, if water is cycled in the apparatus the result is a simplified steam distillation.

In all of the foregoing procedures a body of liquid to be processed is established in a first zone where it is heated by a submerged combustion flame in direct contact with the liquid and incondensible gases are separated from the liquid in a separate zone after which at least a part of the resultant liquid is recirculated to the first zone. For the purpose of making hot water two such zones in the circulating system are required, the first to heat the water and the second to permit separation of the incondensible gases. For the generation of steam, the cracking of petroleum and other processes where condensible vapors are produced, a third zone is desirable and the condensible vapors and/ or other products are recovered or withdrawn from this zone. Many other variations and modifications of the method and apparatus will be apparent to those skilled in the art.

The invention makes it possible to generate steam and to evaporate and process oils and/or chemicals by direct contact of the flame with the liquid and/ or fluids adaptable for use in the process or processes involved. The invention is applicable to processing animal and vegetable oils as well as petroleum or mineral oils. By the direct introduction of heat to fluids or liquids the use of relatively costly metallic equipment for heat exchanger purposes is minimized and at the same time greater heat utilization is attained. While attempts have heretofore been made to generate steam by utililizing submerged combustion, one of the difliculties has been the presence of the incondensible gases admixed with the steam vapor. The present invention makes it possible to produce the steam free from such gases. It is also possible in the practice of the invention to produce hot water for home or factory use.

The invention is hereby claimed as follows:

1. A method of processing a liquid which comprises establishing a body of liquid in direct contact with a submerged flame, establishing a second body of liquid communicating with the first body of liquid by a passageway positioned above said flame whereby the first body of liquid can overflow into the second body of liquid, removing incondensible gases from a space above the second body of liquid, establishing a third body of liquid communicating with said second body of liquid, removing condensible vapors from a space above said third body of liquid, and returning at least a portion of the resultant 6 liquid from said third body of liquid to said first body of liquid at a point below said submerged flame.

2. A method as claimed in claim 1 in which additional liquid to be processed is added to said first body of liquid.

3. A methodas claimed in claim 1 in which a part of said third body of liquid is withdrawn from the system.

4. A method of generating steam which comprises establishing a body of water in direct contact with a submerged flame in a closed system, establishing a second body of water communicating with the first body of Water by a passageway positioned above said flame whereby the first body of water can overflow into the second body of water, removing incondensible gases from a space above the second body of water, establishing a third body of water communicating with said second body of water, removing steam ,from a space above said third body of water, and returning at least a portion of the water from said third body of water to said first body of water at a point below said submerged flame.

5. A method of processing liquid hydrocarbons which comprises establishing a body of liquid hydrocarbons in direct contact with a submerged flame, establishing a second body of said liquid hydrocarbons communicating with said first body by a passageway positioned above said flame whereby said first body can overflow into said second body, removing incondensible gases from a space above said second body, establishing a third body of liquid hydrocarbons communicating with said second body, removing condensible vapors from a space above said third body, and returning at least a portion of the resultant liquid from said third body to said first body at a point below said submerged flame.

6. A process as claimed in claim 5 wherein said submerged flame is formed by burning a fuel gas with not more than the amount of oxygen required for complete combustion.

7. An apparatus for processing a liquid by submerged combustion which comprises a closed heat exchange chamber adapted to hold said liquid, a submerged combustion burner positioned in said chamber, means for recycling a portion of said liquid in a closed system externally of said chamber, means for separating incondensible gases from said liquid during said recycling, and means separate from said second-mentioned means for withdrawing condensible vapors from said recycling liquid.

8. An apparatus for processing a liquid by submerged combustion which comprises a closed heat exchange chamber adapted to hold said liquid, a submerged combustion burner positioned in said chamber, means for recycling a portion of said liquid in a closed system externally of said chamber, means -for separating incondensible gases from said liquid during said recycling, means separate from said second-mentioned means for withdrawing condensible vapors from said recycling liquid, and means for introducing a fluid adjacent the flame produced by said burner.

9. An apparatus for processing a liquid by submerged combustion which comprises a closed heat exchange chamber adapted to hold said liquid, submerged combustion means for burning a fuel in said chamber below the level of said liquid, a second closed chamber, overflow communicating means between said first chamber and said second chamber, an outlet in said second chamber above the liquid level, a second outlet in said second chamber below the liquid level, a third closed chamber communicating with said second outlet, an outlet above the liquid level in said third chamber, an outlet below the liquid level in said third chamber for the recovery of products, and means forming a passageway from a point below the liquid level in said third chamber to said first chamber adapted to permit liquid to flow from said third chamber to a point in said first chamber below the flame produced by said burner.

10. In heating apparatus for heating a fluid by submerged combustion, a first closed vessel containing a submerged cornbustion burner, a second closed vessel positioned in side-by-side relationship with said first vessel, a conduit opening into the upper portion of said first vessel and communicating said vessels for liquid and gas flow from said first vessel to said second vessel, a valved conduit in the top of said second vessel for withdrawing the incondensible gases of combustion emitted by said submerged burner, a third closed vessel, a conduit communie eating a lower portion of said second vessel with said third vessel, means in said last-mentioned conduit for limiting liquid flow only from said second vessel to said third vessel, and a conduit in the top of said third vessel for withdrawing condensible vapors therefrom.

11. The heating apparatus of claim 10 wherein the bottom portion of the first vessel at a point below said burner and a bottom portion of said third vessel are in communication by a conduit extending therebetween, said conduit having means for limiting fluid flow only in the direction from said third vessel to said first vessel, where by at least a portion of the liquid may be recirculated from said third vessel into said first vessel.

12. The heating apparatus of claim 10 wherein the submerged combustion burner comprises a burner plate, a peripheral wall spaced from said burner and defining the chamber surrounding said burner plate, the chamber extending forward of and being open forward of said burner plate in the direction of flame propagation and closed at the opposite end, a second wall extending forward of and surrounding said first-mentioned wall and spaced therefrom to define a peripheral chamber, said peripheral chamber being open at the forward end and closed at the opposite end, and a conduit extending into said first vessel opening into said peripheral chamber for supplying a fluid to the burner in the zone of flame propagation.

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5. A METHOD OF PROCESSING LIQUID HYDROCARBONS WHICH COMPRISES ESTABLISHING A BODY OF LIQUID HYDROCARBONS IN DIRECT CONTACT WITH A SUBMERGED FLAME, ESTABLISHING A SECOND BODY OF SAID LIQUID HYDROCARBONS COMMUNICATING WITH SAID FIRST BODY BY A PASSAGEWAY POSITIONED ABOVE SAID FLAME WHEREBY SAID FIRST BODY CAN OVERFLOW INTO SAID SECOND BODY, REMOVING INCONDENSIBLE GASES FROM A SPACE 